Android Secret Codes List (Samsung, Pixel, OnePlus, Vivo & More)

There are many hidden secret codes on Android phones that let you access hardware test suites, network components and more. You can enter these codes into the Phone app and you can find hidden details about your smartphone. These codes are mainly known to service centre technicians, but in this article, we have compiled a long list of Android secret codes so you can test your device yourself. On that note, let's begin.

What are Secret, Hidden and Diagnostic Codes?

When we say Android secret codes, well, these are not really "secret". These codes are built-in shortcuts that your phone recognises the moment you finish typing them. There are mainly two types of secret codes: MMI and USSD.

First, MMI codes (Man-Machine Interface) are handled by the phone itself. These codes open hardware tests, show your firmware version, open modem info page or launch an engineering menu. As your phone processes them locally, they work regardless of your network operator, but they are tied to the brand.

A code that opens a test screen on a Samsung phone will usually throw an error on an Oppo phone. The codes are different for each brand.

On the other hand, USSD codes (Unstructured Supplementary Service Data) talk to your network instead. These codes let you check your balance, your data usage or your call-forwarding status and they need an active SIM card to do anything. 

The third one is "diagnostic" or "engineering" code, but this is just a casual name for the MMI code that opens the factory test app. Every phone manufacturer adds a diagnostic suite in their phone to check for hardware issues on the production line. This suite is eventually shipped with the phone itself and end-users can also access it to check hardware components.

Most Used Codes on Android

These are the Android codes worth memorising as they work on any Android phone. Here is the table.

Note that *#*#4636#*#* was the code for Android diagnostics for years, but Google has been locking them down since Android 12. It no longer works on modern Android version. Apart from that, the call-forwarding codes (*#21#, *#62#, *#67#, *31# and ##002#) are operator-centric USSD commands rather than phone codes, so they keep working regardless of your Android version.

Android Secret Codes by Phone Brands

Since each Android skin has its own diagnostic app and the codes vary, here are Android codes by phone brands. Bear in mind that each brand has been disabling codes at a different pace, so some codes may or may not work.

Samsung (One UI)

Samsung has a long list of codes among all the Android brands and it offers several hardware tests. I have added some popular Android codes below, but for a detailed list, go through our dedicated Samsung secret codes guide.

Vivo (Funtouch OS / Origin OS)

Many of the Vivo secret codes no longer work on newer Origin OS builds as the company has been aggressively blocking them with each update. However, Vivo phones come with a separate set of secret codes for the accelerometer, gyroscope, proximity sensor, etc., which I have listed in our Vivo sensor check codes guide.

If *#558# does nothing on your model, some Vivo phones respond to ##2288## or ##4777## instead for factory test access. And if you simply want the IMEI number, *#06# is the easiest way to check the IMEI on a Vivo phone.

Oppo (ColorOS)

Oppo has a hidden app called EngineerMode (now called AfterSale) and a single code opens it. We have added all such codes in our Oppo secret codes guide, but here you can find all the important ones.

That said, Oppo started locking these codes from ColorOS 13 onwards, so codes that worked fine on ColorOS 11 and 12 may simply not work on newer versions. By the way, *#06# works on every Oppo phone, which makes it the simplest way to check the IMEI on an Oppo phone.

Realme (Realme UI)

Realme UI is a fork of Oppo's ColorOS, so most Oppo codes work on Realme phones too. Nevertheless, you can find a detailed list of Realme secret test codes from our dedicated article. While Realme has blocked the old *#*#4636#*#* engineering route on most of its phones, you can use *#899# to access the test suite and *#06# for the IMEI.

OnePlus (OxygenOS)

OnePlus also shares its roots with Oppo and that is why its diagnostic app is called EngineerMode. The manual test mode is quite long with around 81 separate checks and I have documented those hidden pages inside our OnePlus secret codes guide.

Xiaomi, Redmi and Poco (HyperOS / MIUI)

Xiaomi has its own hardware test menu called CIT and two codes open it. The CIT menu is brilliant for checking a second-hand Redmi or Poco phone. It lets you test the display, touch panel, sensors, cameras, speakers, mics and more. You can find the much detailed list, including the network and reset codes, in our Xiaomi secret codes guide.

Are Android Codes Safe to Use?

For the most part, yes, Android codes are safe to run. The secret codes that only display information like your IMEI, SAR value, firmware version or signal stats, don't make any changes to your device. The hardware test menus are also harmless as running the speaker or mic test doesn't damage your device

That said, the real risk is associated with two sets of codes. Reset codes like *2767*3855# wipe your data and sometimes with no confirmation. Engineering and CSC codes can change network or calibration settings if you start tapping options inside the menu without knowing what they do.

So, the rule is simple: open the menu, look for values, but don't change anything unless you know what you are doing.

Here are a few practical safety notes before you use Android secret codes. First off, back up your phone before running any code. And importantly, ignore the *#21# code which claims to show if your phone is hacked or not. It does nothing like that and only shows whether call forwarding is switched on. Basically, no code can detect spyware installed on the device.

Common Hardware Test Codes on Android

Display and dead pixels: On Samsung phones, dialling *#0*# gives you solid colours in full-screen mode with Red, Green and Blue. It's the cleanest way to fix white spot or stuck pixels on the screen. On Xiaomi, the CIT menu (*#*#64663#*#*) offers the same display test. Look for a white or black screen to catch white spots and backlight bleed.

Touchscreen: Samsung's *#0*# and Xiaomi's *#*#64663#*#* code lets you perform a touchscreen test. You basically drag a finger across the whole panel to confirm every touch registers. This is the quickest way to find a dead zone after a screen replacement.

Sensors: The accelerometer, gyroscope, proximity sensor, ambient light sensor and compass all offer live values in the hardware test menus or EngineerMode. Check the table above to find the code to open the test suite or EngineerMode.

Audio: Samsung's *#0283# code runs loopback test which plays whatever the mic picks up straight through the speaker or earpiece. It's done to catch a mic fault within seconds. You can find speaker and mic checks for other brands into their main test menus.

IMEI and Serial Number Code on Android

The IMEI is the 15-digit number that identifies your phone on any mobile network. You can dial *#06# on any Android phone to show the IMEI number. If you have a dual-SIM phone, you will see two IMEI numbers. For phones running One UI, you can follow our guide and learn how to check the IMEI number on Samsung phones. 

The same *#06# code also shows the serial number on some Android phones. You can follow our article and see how to check serial number on Realme phones. Keep in mind that the serial number is different from the IMEI number. Serial number is assigned by the device manufacturer and it's used for verifying authenticity of the device while IMEI number can be used to track your device across all mobile networks in the world.

Reset, FRP and Emergency Codes on Android

This is the section where you will find sensitive Android codes as they have have real consequences. While most of the codes are patched on recent versions of Android, if you run these codes on older builds, you may end up wiping your device.

Reset codes: First off, *2767*3855# triggers a full wipe and firmware reinstall on Samsung and several older Android phones. Secondly, *#*#7780#*#* is the softer reset  code on some devices. My advice is to never use a reset code for a routine factory reset and use Settings where you get a proper confirmation step.

FRP (Factory Reset Protection): This is actually a security layer that asks for your previously synced Google account after a reset. There is no secret code that bypasses FRP in 2026. Codes can only check lock status, but never remove it.

Emergency codes: If you suspect, your calls are being diverted, simply dial ##002# to disable all call forwarding on your Android phone. It can prevent financial scams by stopping call-based OTPs.

And that wraps up our detailed article on Android secret codes. You don't need to remember the whole list. Just keep *#06# handy for IMEI number check and remember the hardware test code for your device. These codes will help you perform a quick lookup on your device.